The inserted transgene contained a 1.1kb fragment of the Eno2 promoter region driving a cre open reading frame with a nuclear localization signal. Expression of the transgene is seen in developing and adult brain. At 9.5- 13.5 d.p.c recombinase activity is detected in forebrain, hindbrain and along the midbrain flexure. in adult brain, recombinase activity is observed in cerebral cortex, cerebellum, hippocampus, cortex and septum.